The Natural Course of Pain in Fibrous Dysplasia/McCune Albright Syndrome: A Prospective Follow Up Study.

Fibrous dysplasia/McCune-Albright (FD/MAS) syndrome is a rare bone disorder with a broad clinical manifestation. Pain is the most frequently reported complaint and can significantly impair quality of life. While most existing data are cross-sectional, little is known about symptom progression over time. This study aimed to assess changes in pain and QoL over 2 years follow-up. Patients in the PROFID study completed yearly questionnaires aligned with check-ups or independently if check-ups were less frequent. At baseline, 143 (85.6%) reported pain, of which 38 (26.6%) mild, 105 (73.4%) moderate/severe pain, and 24 (14.4%) had no pain. Emotional wellbeing and energy/fatigue were the most affected in the SF-36 domains. Patients viewed their disease as chronic, with moderate daily fluctuation and impact showed that active and palliative coping were the most frequently used coping mechanism. After 2 years, 27.4% of those with no or mild pain at baseline reported a significant increase in pain (1.3-5.0, p < 0.001), while scores in the moderate/severe group remained stable (6.6-6.3, p = 0.5). Emotional wellbeing improved significantly (37.6-55.5, p < 0.001). Patients with moderate/severe pain reported increased disease control, whereas those with no/mild pain felt less control (p = 0.01). Higher pain scores correlated with poorer physical (r = - 0.627), social (r = - 0.541), and general health (r = - 0.452), worse illness perceptions (e.g., illness identity r = 0.3), and greater palliative coping (r = 0.4), all p < 0.05. These findings emphasize the need to address both physical and psychological aspects of FD/MAS.